[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

The surface and materials science of tin oxide

The interaction of water with solid surfaces: Fundamental aspects

The Interaction of Water with Solid Surfaces: Fundamental Aspects Revisited

Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40th anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful theoretical methods are dee...

Fundamentals and Catalytic Applications of CeO2-Based Materials

Nanophase Fluorite-Structured CeO2–ZrO2Catalysts Prepared by High-Energy Mechanical Milling☆

The adsorption and surface reactions of acetaldehyde at 300–673 K on TiO2, CeO2 and Al2O3 were investigated by Fourier transform infrared spectroscopy and mass spectroscopy. Acetaldehyde adsorbs molecularly in two forms on the surfaces: (i) in a less stable H-bridge bonded form and (ii) in a more stable form adsorbed on Lewis sites through one of the oxygen lone pairs. Both forms of molecularly adsorbed acetaldehyde transform into crotonaldehyde (CH3CH–CHCHO) by b-aldolization on the surfaces. The reaction of adsorbed acetaldehyde and crotonaldehyde resulted in the formation of benzene at higher temperature. The formation of crotonaldehyde and benzene depended on the nature and the pre-treatments of the oxides: the amount of crotonaldehyde was higher on H2-pre-treated, while the amount of benzene was higher on O2-pre-treated surfaces. Primarily the more strongly held acetaldehyde underwent dehydrogenation resulting in H2 and acetylene. The formation of ethane was interpreted by hydrogenation of the transitorily formed ethylene and/or by catalytic decomposition of ethanol, which formed from adsorbed ethoxy produced by the surface reduction of acetaldehyde. Acetaldehyde could be oxidized into acetate, the decomposition of which resulted in gas phase methane. No CO and CO2 was detected up to 673 K. # 2005 Elsevier B.V. All rights reserved.

/pdf/adsorption-and-surface-reactions-of-acetaldehyde-on-tio2-fxpkmhsykx.pdf

Adsorption and surface reactions of acetaldehyde on TiO2, CeO2 and Al2O3

The interaction of formaldehyde with Pt/TiO2 and Au/TiO2 catalysts was investigated at 300–473 K by Fourier transform infrared spectroscopy and mass spectrometry. The effects of the pretreatments and the metal content of the catalysts, as well as the effects of the reaction temperature on the formation of the surface species and on the gas phase products were studied. Molecularly adsorbed formaldehyde, formic acid, formate, dioxymethylene and polyoxymethylene surface species are formed during formaldehyde adsorption at 300–473 K. The main gas phase products were H2 and CO; their amounts increased with the increase of the metal content of the catalysts and with the increase of the reaction temperature. Gas phase ethylene, acetylene, as well as formic acid were detected on pure TiO2. On metal-containing TiO2 no ethylene, acetylene and formic acid were observed, which could be connected with the limited surface concentration of oxygen vacancies on these surfaces.

/pdf/ftir-and-mass-spectrometric-studies-on-the-interaction-of-4tmivi3z8s.pdf

FTIR and mass spectrometric studies on the interaction of formaldehyde with TiO2 supported Pt and Au catalysts

The effect of the nature of the support and the promotion achieved by a Rh additive on Co-based catalysts in the ethanol steam reforming reaction were studied. The catalysts with 2% Co loading were characterized by temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). In situ diffuse reflectance Fourier-transform infrared spectroscopy (DRIFTS) identified the surface intermediates formed during the reaction, whereas gas phase products were detected by gas chromatography (GC). Upon heating in hydrogen to 773 K, cobalt could not be reduced to Co0 on alumina, but on silica the reduction was almost complete. On ceria, half of the Co could be reduced to the metallic state. By the presence of a small amount (0.1%) of Rh promoter, the reduction of both cobalt and ceria was greatly enhanced. For Co on the acidic Al2O3 support, the dehydration mechanism was dominant, although on the basic CeO2 support, a significant amount of hydrogen was also formed. Addition of a small amount of Rh as...

/pdf/effects-of-support-and-rh-additive-on-co-based-catalysts-in-1gagr376tu.pdf

János Kiss

Papers

Nanophase Fluorite-Structured CeO2–ZrO2Catalysts Prepared by High-Energy Mechanical Milling☆

Adsorption and surface reactions of acetaldehyde on TiO2, CeO2 and Al2O3

FTIR and mass spectrometric studies on the interaction of formaldehyde with TiO2 supported Pt and Au catalysts

Effects of Support and Rh Additive on Co-Based Catalysts in the Ethanol Steam Reforming Reaction

Formaldehyde formation in the interaction of HCOOH with Pt supported on TiO2